W123 Inner drive shaft boot (and what its filled with)?

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Active Member
Nov 10, 2005
West Sussex
CLK230Kompressor (factory AMG sport pack) & Jaguar XJ8 (X308)
Hi All - I thought i had a rear differential leak as i started to see some fluid on the floor at the back of the car (only a few drops) but it turned out to be a split in the boot covering the inner part of the rear drive shaft.
I was a little perplexed as i thought it may have been packed with grease - however, I understand its filled with gear oil??

my question is - When I replace the boot, do I use grease or do i somehow have to fill with gear oil?

Pic for reference (not my car).....

do I use grease or do i somehow have to fill with gear oil?

We've just done that on my 124. I bought SKF (I think) boot kits and they included all the new screws, clips, boots and grease. Not oil but grease.


Good luck.

If its oil filled i would imagine it would be filled as you fill the diff.
If its grease just pack it and fit.
I have used those 2 piece boots in the past which you glue together over the shaft if there's one available for your model, saves a lot of faff and stripping down.
Sounds a bit of a bodge to me.
Not really if done correctly, cleanliness is the key to it. Used them many times in the past. Why waste time and money and possibly doing more damage when stripping out the shaft to fit it. A plastic bag, tub of grease and some string is a bodge but it will get you home. 😇
Not really if done correctly, cleanliness is the key to it.

I was sounding a bit judgemental - didn't mean to. So they do work?

I ask as we have done the whole thing at significant cost but it is after half a million Kms so justified. It also included a lot of other stuff like new bearings, flanges, handbrake assemblies, disc shields and clean and paint of everything.

Long may it last.

Split glue together drive shaft boots from long past experience are ...I'll be polite not very good.
However, if they are oil filled from factory there's a very good reason that it is oil and not grease? What grade is it though? I have similar on my r107 450SL.anybody no the answer ???
I've neve seen any "boot" on any model of car filled with oil....its just not what's done.....How would you fill it for a start!!???. If "oil" is leaking out its either hot melted grease.....or more likely oil that leaked into it from the diff.
Thanks for your espouse, however you are so wrong it is not melted grease, it is also not leaking oil from the diff, it is oil in both joint housings that contain the c.v.joints ,it IS as stated, sorry if this comes across as a little harsh, it's not meant too so please don't take offence
If it is some type of oil it can only be filled from the diff filler so i can only presume that it doesn't have shaft seals. If thats the case i would think its somthing like EP90.
The shafts are filled with oil prior to been fitted to the differential! nothing to do with oil from the diff there is no connection of oilways between shaft and diff,
Now I am confused. The shaft is filled with oil ? So oil is somehow poured/injected along the drive shaft to lubricate one side of the bearing on the diff , the other side (internal part of the diff) is lubricated by oil in the diff sump ?

I am not saying the concertina boot should so no signs of 'thin' oil inside it but it is something I personally never seen unless the seal it is covering has failed . Normally you might find a greased mechanism/bearing behind what is essentially a weather/dirt/dust sealing device (the boot) .

I would be happy to be proved wrong by a real mechanic on here .
Agreed....I cant see how you could possibly fill a boot with oil and then clamp it in place!!

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